Automatic power driven pipe wrench



June 23, 1931. w. w. FOSTER AUTOMATIC POWER DHIVEN PIPE WRENCH Filed DeG. 14, 1929 W Wim ./A/'I/f/VTR A T TURA/EY Patented June PAT-ENT OFFICE WALTER FOSTER, OF WICHITA FALLS, TEXAS, ASSIGNOR TO HILL & FOSTER COM- .PANY INCORPORATED, OF WICHITA FALLS, TEXAS 'AUTOMATIC POWER DRIVEN PIPE WRENCH Application led December 14, 1929. Serial No. 413,990.

This invention relates to pipe and casing handling apparatus and it has particular reference to a power driven wrench, the principal object of the invention being to provide wholly automatic means, in an apparatus of the character designated for simultaneously gripping and rotating cylindrical or tubular elements, such as Well casing, in jointing and unjointing a casing assembly in oil well operations, and to thus minimize the time and eEort usually required in vthese operations.

Another object of the invention resides in the provison of an automatic wrench wherein is arranged a series of gripping elements piv- 115 otally disposed upon a movable ring and constrained to collectively move toward a common center to grasp and hold an object while the latter is rotated by motion transmitted to rotate the ring upon which said elements are mounted, and likewise capable of automatic release.

Broadly, the invention comprehends the provision of a power wrench having a minimum number of parts, yet so disposed and arranged as to bring about a compound force to rotate a heavy object with comparatively little strain upon the parts, and consequently little wear.

With the foregoing objects as paramount,

the invention has still further and lesser objects which will become manifest as the description proceeds directed to Athe sallent features of the invention and details of construction, taken in connection with the accompanying drawings, wherein;

Figure l is a perspective view of an automatic wrench constructed according to the present invention.

Figure 2 is a vertical sectional view taken longitudinally through Figure 1, and

Figure 3 is a diagrammatic view of one of the gripping elements and in operation.

Particularly, in the handling of pipe and tubingof large diameter, such as setting up and breaking out well casing, assembling the drill stem and other similar uses, there has been a long felt need and consequent demand for automatic machinery of practical and durable constructionfor screwin and unscrewing pipe .sections in assem ling and breaking out strings in a well. Due to the tong on the work, untimely release of the tong handle while the latter is under strain and many other causes.

The present invention is designed to minimize the danger attending thework above referred to as well as to reduce the effort and generally improve conditions surrounding the handling of pipe in the manner explained.

Accordingly, the present invention is comprised primarily of a base 1, consisting of a casting having an exterior annular flange 2 and an inner flange 3, concentric in relation to the outer ange, and providing an intermediate recess in which reposes a ring gear 4, having teeth a on the outside, corresponding with those on the worm 5, situated in a housing 6c-ast integral with the base 1. The gear 4 is likewise provided with gear teeth b on its inner surface, the purpose of which will be explained presently.

It is understood that the ring gear 4 is mounted to freely move in the annular recess between the flanges 2 and 3 of the base 1, motion being imparted thereto to rotate the same, from the worm 5. The iianges 2 and 3 prevent any lateraldisplacement of the gear 4, thereby insuring against undue strain at any point when a load is placed thereon. v

Near aperture c in the structure, through which the work is passed, is a loose ring 6, held against displacement by the annular casting 3 on the outside and the inner flange 7 formed on the base 1. This latter iiange is substantially reinforced by -a rib 8, built up to afford a sort of guide, to directcouplings and tool joints through the opening c and prevent jarring the device as a section of pipe is let into the hole preparatory to threading the same into another section.

A rigid and substantially strong frame 9 of channel iron or the like is bolted to and extends rearwardly of the base 1 of the invention, and which frame supports a gear transmission housing 10 in which is contained conventional friction transmission gears for transmitting motion from the conventional electric motor 11, likewise supported on'the frame 9, to the drive shaft 12. Upon the end of this latter shaft is mounted a beveled gear 13, cooperating with a gear 14, situated upon the end of the worm shaft 15 to drive the worm, which in turn, drives the large ring gear 4, and reduces speed of same.

It is not considered necessary to embody in this description a detailed description of the transmission gearing, other than to mention that it contains the usual assembly of gears necessary to transmit power sufficient to break a threaded joint of pipeand spin out the same in the usual time. Moreover, it may be stated in further regard to the transmission employed in connection with the invention that it will not be required to alter the conventional friction clutch contained therein to accomplish that for which the invention is intended. This friction clutch is adjusted to assume the load to prevent overloading the motor 11 and probably burning it out, atthough motors of the type employed in connection with this invention are usually equipped, when used for heavy duty, with magnetic throw-off switches as quenchers which are actuated by the overload to cut off motor vcurrent and again funciton when the load is reduced.

The motor and transmission described in the foregoing are not considered herein as new, and are subject to change from time to time to suit the conditions under which the invention is employed. It may be mentioned however, at this point that special motors are constructed for use in supplying power under conditions ordinarily considered dangerous, due to ignition of petroleum products in well drilling, creating re hazards. Such a motor is contemplated for use for supplying the necessary driving power for the invention, although steam turbines, internal combustion engmes and like power plants may be substituted for the electrically driven motor with probably sirable results.

Referring again to the invention and its associated parts, it will be observed that a plurality of work gripping elements 16 are provided and Divoted to the sliding ring 6 in equidistantly 4spaced relationship. These gripping elements are each eccentrically pivoted at d to the said ring 6 so that the lobe 17 thereof will be thrown outward simultaneously when the ring gear 4 is moved in a equally as pleasing and deof the moving parts of the structure are very effectively concealed by means of a cast plate 18, shown fragmentarily in Figure 1 and sell cured to the outer flange 2 of the apparatus by means of bolts 20. The plate 18 is formed to define an annular raised portion 2l, similar to that formed on the hase casting, surrounding the opening c, also to guide the sections into engagement preparatory to making or breaking the joint.

A small cover 22 is provided for the worm housing 6 and is held in position by means of bolts 23. Suitable packing may be provided between the said cover and housin to effectively retain the lubricating medlum contained within the said housing and in which the worm 5 operates. A grease filler opening 24 is situated upon the housing 6 to afford a means for keeping the parts thoroughly lubricated. The lubricating medium contained within the housing 6 is yielded to the other moving parts in sufficient quantities to keep them suitably well lubricated.

Having described the preferred embodiments of the invention, its advantages and uses, its operation as applied in connection with well drilling operations will be set forth.

The apparatus is intended to be yieldingly suspended by a line over a fixed pulley in the derrick and counterbalanced to enable it to be raised and lowered with ease. The top section of the casing or drill stem assembly, as the case may be is suspended by the conventional pipe elevator, through the opening c, whereupon the lever 25 is actuated to throw the motor shaft in gear with the drive shaft 12, thereby rotating the worm 15, which latter imparts rotary motion to the ring gear 4.

It will be understood that since the ring 6, to which the gripping elements 16 are pivoted is frictionally movable, it will remain motionless during rotation of the ring gear until such time as each of the gripping elements 16 are moved outwardly to the extreme extended position, or into engagement with the work. When such action occurs, the elements 16 become instantly operative to enage and rotate the work, and in the case of reaking the joint, the initial force applied is required to be greater than the rotating movement in spinning out the section, therefore it is desirable that the initial movement of the gripping elements, both in the rotary as' well'as in the inwardly converging action be accomplished with quick impetus to obthe conventional friction clutch and magnetic switch.

In order to withdraw the gripping elements to retiring position, the reverse lever 26 is actuated to reverse the direction of rotation of the ring gear to move the elements 16 on their pivots to a position beneath the plate18.

The foregoing description deals with both, setting up and breaking out drill stem and casing assemblies, but it is specifically pointed out that the invention is shown in the drawings as being prepared for setting up casing, since each of the gripping elements 16 are so situated as to move to operative position when the yring gear 4 is rotated in a clockwise direction, hence the gripping elements will be so moved and thus will the pipe section held thereby be moved to thread in the joint.

In order that the invention may operate to.

break out drillstem sections, it becomes necessary that the gripping elements 16 be inverted, reversing the position of the knurled lobular portions relative to the work, and

and an extended portion to receive a frame, the said frame being rectangular in shape and extending from said casting to support power supplying means, a ring gear disposed to rotate between the flanges of said casting having gears on its inner and outer eripheries, spaced, cam shaped members aving gears engageable with the gears on the inner periphery of said ring gear and rovided with teeth projecting inwardly in t e direction of the openin in said casting, a cover conforming to said casting and having an opening in register with said casting and likewise having a beveled approach to its opening, and means4 for transmitting rotary motion to said ringgear from said power supplying means.

In testimony whereof I aix m signature.

WALTER W. OSTER. l

obviously by reversing the direction of the j ring gear 4, the same gri ping action is obtained on the work by t e elements, as before. To reverse the gripping elements to obtain the reversixil e ect above described, an opening 27 is m e in the cover 18 in order that access to the pivot bolts d maybe readily obtained. These bolts d are thus removed and the grippin elements slid out from their position beneat the cover 18 reversed end for end and reinserted, whereupon the bolts are replaced. Thus, the apparatus is prepared for breaking out operations as previously` explained., V

vIn which the gripping e ements 16 are actuated in the spinmng in operations by showing one of said elements in full, and suggesting in broken lines the displaced or operative positiolp of the element when engaged with the wor Though the invention has been describe witihogreat particularity, the detailsv ofthe em iment of the invention herein shown are not to be construed as being limited thereto, as changes in arrangement and substitution of equivalents vmay be made by those skilled in the art without departin from the invention as defined in the appen ed claim.

What is claimed is:

In an automatic power driven pipe wrench, the combination including a. casting having a circular portion with inner and outer having a beveled approach to laid opening igure 3 issu gestedthe manner in l 

